The invention relates to catheters for continuous drainage of fluids from cavities of the body, and more particularly, to catheters of the implantable kind for the drainage of urine from the kidney and into the bladder.
Catheter stents are used to promote fluid drainage through damaged bodily passages. For example, catheter stents are used in the ureter when a cancerous growth is interfering with drainage of urine from the kidney. Also when the ureter has been damaged, for example in an auto accident, catheter stents are used to prevent leakage of urine through incisions in the urinary tract. Ureteral catheter stents are used when other types of damage have occurred in order to prevent acute angulation of the ureter during healing.
The stent is usually positioned in the desired fluid passage by insertion into and through a body orifice, incision, peripheral artery, vein, urogenital or respiratory passage. Once the need for the stent has been eliminated, however, the stent must be removed. Removal is preferably accomplished without surgery. Absent complications, ureteral catheter stents can be removed by grasping the bladder end of the stent and removing the stent through the urogenital passage. Without proper anchoring, however, a ureteral catheter stent can migrate either into the bladder or into the kidney. If the stent migrates into the kidney, surgery will be required to remove the stent. Migration not only complicates removal of the stent, but also interferes with proper fluid flow through the fluid passage being drained.
One factor which increases the possibility of migration of a stent is improper measurement of the stent in relation to the fluid passage being drained. For example, ureteral catheter stents are presently commercially available in lengths that increase by four centimeter increments for 12 to 30 centimeters. The patient having a fluid passage of a length different than these three commercially available stent lengths must bear the increased risk of stent migration or irritation. The unavailability of more varied stent lengths is not only a burden on patients, but also on hospitals. Presently, hospitals must use valuable inventory space to maintain inventory of all sizes of catheter stents.
The foregoing problems reveal the need for a catheter stent which can be more precisely measured to fit patients' needs but which helps decrease the required hospital inventory. The present invention is designed to meet these needs.